Giardiasis Pattern among Different Age Categories: Childhood Assemblage B Proclaim Endemicity

Area of Science:

• Medical Parasitology
• Molecular Epidemiology
• Infectious Diseases

Background:

• Giardiasis, caused by *Giardia intestinalis*, is a widespread intestinal parasitic infection.
• Understanding the distribution of *Giardia intestinalis* assemblages is crucial for disease control.

Purpose of the Study:

• To determine the prevalence and patterns of *Giardia intestinalis* assemblages in symptomatic patients aged 2-40 years.
• To identify potential risk factors and clinical associations with specific *Giardia intestinalis* assemblages.

Main Methods:

• Microscopic and molecular (semi-nested PCR) examination of stool samples from 278 patients.
• Genotyping of *Giardia intestinalis* isolates using PCR-restriction fragment length polymorphism (PCR-RFLP) targeting *gdh* and *bg* genes.
• Analysis of gene sequences for assemblage identification.

Main Results:

• Assemblage B (69.6%) was more prevalent than Assemblage A (17.4%) among 23 successfully genotyped isolates.
• Sub-assemblages AII and BIII predominated at the *gdh* locus.
• Infection with Assemblage B peaked in the 6-12 year age group (87.5%) and was associated with diarrhea and abdominal pain.

Conclusions:

• Assemblage B is the predominant *Giardia intestinalis* type in symptomatic children and young adults.
• Physicians should consider giardiasis Assemblage B in pediatric patients presenting with diarrhea and abdominal pain.
• Age, specifically late childhood, is a significant risk factor for Assemblage B infection.